Conventionally, there are proposed a large number of apparatuses for detecting entering and/or leaving of a target such as a person into and/or from a specific area such as a security area.
The apparatus of this type is roughly divided into two parts. The apparatus of a first type serves to detect entering and/or leaving of a person into and/or from a specific area provided with a locking apparatus, an entry door and/or a gate. The apparatus of a second type can also detect entering and/or leaving of a person into and/or from a so-called open specific area (which will be hereinafter referred to as an open area) which is not provided with a locking apparatus, an entry door and/or a gate.
Patent literature 1, patent literature 2, patent literature 3 and the like disclose an example of the apparatus of the first type. Moreover, patent literature 4, patent literature 5 and the like disclose an example of the apparatus of the second type.
The apparatus of the second type has an advantage that an application range is wider than that in the apparatus of the first type in that it can also be applied to the open area which is not provided with the locking apparatus, entering/leaving and/or the gate.
Patent literature 4 discloses an apparatus for detecting a person by means of a monitoring camera and deciding whether or not a suspicious person enters a specific area based on a position of the detected person, a position of the specific area and a staying duration of the person.
Patent literature 5 discloses an apparatus for deciding whether a portable terminal (a person) exists an inside of a specific area or an outside of the specific area based on a relative positional relationship between a result of a position measurement of the portable terminal and a boundary of the specific area.